Electrically interlocking pushbutton circuit with error indication

ABSTRACT

An electrically interlocking pushbutton circuit with error indication is disclosed, including two locking-type pushbuttons which are electrically interlocked such that a first operated pushbutton must be released before the second can be operated to initiate a related function. If the first pushbutton is not released, a flashing error indication is provided, by means of an indicator lamp associated with each of the pushbuttons.

United States Patent Herr [ Jan. 22, 1974 INDICATION PrimaryExaminerl-lerman J. Hohauser Assistant Examiner-M. Ginsburg Attorney,Agent, or Firm-Bernard E. Franz [75] Inventor: Kurt F. Herr, Woodridge,Ill.

[73] Assignee: GTE Automatic Electric Laboratories Incorporated,Northlake, Ill. [57] ABSTRACT [22] Filed: Apr. 6, 1973 1 l k hb h Anelectricaly inter oc ing pus utton circuit wit [21] Appl 348570 errorindication is disclosed, including two lockingtype pushbuttons which areelectrically interlocked [52 US. (:1. 307/115, 340/175.2 R h that afirst Operated pushbutten must be released 51 1111. c1. 110111 47/00before theseeend can be operated to initiate a related [58] Field ofSearch 307/112, 113, 115, 92; function If the first pushbutten is oreleased, a 179/1752 R, 175,21; 200/167 A; 340/331 flashing errorindication is provided, by means of an 292, 252 R; 317/123 indicatorlamp associated with each of the 'pushbuttons.

[56] References Cited UNITED STATES PATENTS 9 Claims, 1 Drawing Figure3,179,777 4/1965 Rohacs "200/167 A 50V v 50V RA RB ms RAJ 7 R83 R8 Ll 7F E/T LOCK/N6);

I20 IPM 6RD PULSES ELECTRICALLY INTERLOCKING PUSHBUTTON CIRCUIT WITHERROR INDICATION This invention relates to an electrically interlockingpushbutton circuit with error indication.

BACKGROUND OF THE INVENTION The electrically interlocking pushbuttoncircuit with error indication of the present invention has numerousapplications where, for example, during testing of various differentpieces of equipment or circuits, a first operated pushbutton, whichestablished a first test condition, must be restored prior to operatinga second pushbutton which establishes a second test condition, toprevent damaging the test equipment. A particular application is in atest desk used in a telephone exchange, for testing various trunksand/or lines by connecting different test circuits to them. Such a testdesk may be of the type disclosed in a copending application entitltedManually Controlled Connect Matrix, Ser. No. 348,561, filed Apr. 4,1973, by Kurt F. Herr.

In such an application, as an example, the simultaneous application of+100 volts coin collect voltage and --l volts coin refund voltage duringtesting must be prevented. Correspondingly, the application of --ISvolts and ISO volts test battery must be prevented. Numerous othersimilar conditions exist.

In addition to preventing two such test conditions from beingsimultaneously applied, a testman should also receive an indication thatan error was made.

Accordingly, it is an object of the present invention to provide animproved electrically interlocking pushbtton circuit with errorindication.

Still another object is to provide such a circuit which is relativelyinexpensive, and relatively simple in construction and operation.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the several steps and the relationof one or more of such steps with respect to each of the others and theapparatus embodying features of construction, combination of elementsand arrangement of parts which are adapted to effect such steps, all asexemplified in the following detailed disclosure, and the scope of theinvention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWING For a fuller understanding of thenature and objects of the invention, reference should be had to thefollowing detailed description taken in connection with the accompanyingdrawing, in which:

The single FIGURE is a schematic illustrating an electricallyinterlocking pushbutton circuit with error indication exemplary of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT light 11 are associated with thepushbutton PB as described more fully below. An energizing source 12which may be, for example, a [PM ground pulse, is providedfor energizingthe lights 10 and 11, to provide a flashing error indication. The relaysRA and RB have additional contacts for initiating other functions,however, they are not pertinent to the present invention.

When one of the pushbuttons, for example, PBl is pushed, it closes itsnormally open contacts PBL, and FBI to extend ground through itsnormally open contact PBL, and the normally closed contact RBZ of relayRB to energize the relay RA. At contact PBl,,, an error energizingcircuit for the lights 10 and 11 is prepared, as more fully describedbelow. Relay RA in operating closes its normally open contact RA, toextend ground to energize the light 10, and opens its normally closedcontacts RA2 and RA;;. The light 10 will glow brightly indicating thatthe pushbutton PB] has been operated. The contact RAz opens the ener'gizing circuit for the relay RB, thus preventing it from being energizedshould the pushbutton PB2 now be operated. The contact RA3 opens theerror indicating energizing circuit to the light 10.

If now the pushbutton PB2 is operated to close its normally opencontacts P82 and p32 ground is extended through the contact PB2 toenergize the relay RB, however, with the contact RA open, relay RB isnot energized. The source 12 is extended through the contacts P31 andPB2 both of which are now closed and through the normally closed contactRB to the light 1 1 to energize it. The light 11 will be flashed at the120 [PM rate, thus indicating the error inoperating the push-button PB2,prior to restoring the pushbutton PBl.

At this time pushbutton PB2 can be restored, without the first testconfiguration or function established when the pushbutton P8] wasoperated being interrupted. Alternatively, pushbutton PBl can berestored, and the test configuration or function which is established byoperating the pushbutton PB2 will be set up.

If the pushbutton PB2 is operated first, the subsequent operation ofpushbutton PBl will be ineffective, and the light 10 will be caused toflash, as described above.

Accordingly, with this simple arrangement, it can be seen that only onetest configuration at a time can be established, by the operation ofeither the relay RA or RB, and if the other one of the two pushbuttonsis operated without first restoring the operated pushbutton, an errorindication is provided.

' While specific reference is made to a pushbutton, it will beappreciated that any type of switch having contacts operated in thedescribed fashion can be use in the circuit. Accordingly, the termpushbutton is used in a generic sense to cover these types of switchesalso.

It will thus be seen that the objects set forth above among those madeapparent from the preceding description, are efficiently attained andcertain changes may be made in carrying out the above method and in theconstruction set forth. Accordingly, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

Now that the invention has been described, what is claimed as new anddesired to be secured by Letters Patent is:

1. An electrically interlocking pushbutton circuit with error indicationcomprising, in combination: a first pushbutton having a relay includinga plurality of contacts and a light associated with it, said relay andsaid light normally being energized when said first pushbutton isoperated; a second pushbutton having a relay including a plurality ofcontacts and a light associated with it, said relay and said lightnormally being energized when said second pushbutton is operated; anenergizing source for energizing said lights to provide an errorindication; the arrangement comprising means such that the operation ofone of said first and second pushbuttons energizes the relay and thelight associated with it, prepares an energizing circuit from saidenergizing source to said lights, said relay in being energized openingthe energizing circuit for the relay associated with the other one ofsaid pushbuttons and opening the prepared energizing circuit from saidenergizing source to its associated light, and such that the operationof the other one of said first and second pushbuttons with out restoringthe first closes the prepared energizing circuit from said energizingsource to the light associated with the second operated one of saidfirst and second pushbuttons to cause it to light to provide an errorindication.

2. The electrically interlocking pushbutton circuit with errorindication of claim 1, wherein said energizing source comprises aninterrupted source whereby said light associated with the other one ofsaid first and second pushbuttons is caused to flash to provide saiderror indication.

3. The electrically interlocking pushbutton circuit with errorindication of claim 1, wherein said first pushbutton comprises a firstand a second normally open contact, said first normally open contactbeing included in the energizing circuit for the relay associated withsaid first pushbutton and being closed when the latter is operated toenergize said relay, said second normally open contact being included inthe energizing circuit for energizing said lights and being closed whensaid first pushbutton is operated to prepare said energizing circuit forsaid lights.

4. The electrically interlocking pushbutton circuit with errorindication of claim 3, wherein said relay associated with said firstpushbutton comprises a normally open contact included in the energizingcircuit for said light associated with said first pushbutton, a firstnormally closed contact included in the energizing circuit for the relayassociated with said second pushbutton and a second normally closedcontact included in the energizingcircuit from said energizing source tosaid lights, said relay upon being energized closing said normally opencontact to light said light associated with said first pushbutton andopening said first and second normally closed contact to thereby openthe energizing circuit for said relay associated wtih said secondpushbutton and the energizing circuit for said energizing source to saidlight associated with said first pushbutton.

5. The electrically interlocking pushbutton circuit with errorindication of claim 3, wherein said second pushbutton comprises a firstand a second normally open contact, said first normally open contactbeing included in the energizing circuit for the relay associated withsaid second pushbutton and being closed when the latter is operated toenergize said relay, said second normally open contact being included inthe energizing circuit for energizing said lights and being closed whensaid second pushbutton is operated to prepare said energizing circuitfor said lights.

6. The electrically interlocking pushbutton circuit with errorindication of claim 5, wherein said relay associated with said secondpushbutton comprises a normally open contact included in the energizingcircuit for said light associated with said second pushbutton, a firstnormally closed contact included in the energizing circuit for the relayassociated with said first pushbutton and a second normally closedcontact included in the energizing circuit from said energizing sourceto said lights, said relay upon being energized closing said normallyopen contact to light said light associated with said second pushbuttonand opening said first and second normally closed contact to therebyopen the energizing circuit for said relay associated with said firstpushbutton and the energizing circuit from said energizing source tosaid light associated with said second pushbutton.

7. The electrically interlocking pushbutton circuit with errorindication of claim 6, wherein said energizing source comprises aninterrupted source whereby said light associated with said secondpushbutton is caused to flash to provide said error indication.

8. The electrically interlocking pushbutton circuit with errorindication of claim 7, wherein the energizing circuit from saidenergizing source to the light associated with said first pushbuttonincludes said second normally open contacts of both said first andsecond pushbutton and said second normally closed contact of the relayassociated with said first pushbutton.

9. The electrically interlocking pushbutton circuit with errorindication of claim 8, wherein the energizing circuit from saidenergizing source to the light associated with said second pushbuttonincludes said second normally open contacts of both said first andsecond pushbutton and said second normally closed contact of the relayassociated with said second pushbutton.

1. An electrically interlocking pushbutton circuit with error indicationcomprising, in combination: a first pushbutton having a relay includinga plurality of contacts and a light associated with it, said relay andsaid light normally being energized when said first pUshbutton isoperated; a second pushbutton having a relay including a plurality ofcontacts and a light associated with it, said relay and said lightnormally being energized when said second pushbutton is operated; anenergizing source for energizing said lights to provide an errorindication; the arrangement comprising means such that the operation ofone of said first and second pushbuttons energizes the relay and thelight associated with it, prepares an energizing circuit from saidenergizing source to said lights, said relay in being energized openingthe energizing circuit for the relay associated with the other one ofsaid pushbuttons and opening the prepared energizing circuit from saidenergizing source to its associated light, and such that the operationof the other one of said first and second pushbuttons without restoringthe first closes the prepared energizing circuit from said energizingsource to the light associated with the second operated one of saidfirst and second pushbuttons to cause it to light to provide an errorindication.
 2. The electrically interlocking pushbutton circuit witherror indication of claim 1, wherein said energizing source comprises aninterrupted source whereby said light associated with the other one ofsaid first and second pushbuttons is caused to flash to provide saiderror indication.
 3. The electrically interlocking pushbutton circuitwith error indication of claim 1, wherein said first pushbuttoncomprises a first and a second normally open contact, said firstnormally open contact being included in the energizing circuit for therelay associated with said first pushbutton and being closed when thelatter is operated to energize said relay, said second normally opencontact being included in the energizing circuit for energizing saidlights and being closed when said first pushbutton is operated toprepare said energizing circuit for said lights.
 4. The electricallyinterlocking pushbutton circuit with error indication of claim 3,wherein said relay associated with said first pushbutton comprises anormally open contact included in the energizing circuit for said lightassociated with said first pushbutton, a first normally closed contactincluded in the energizing circuit for the relay associated with saidsecond pushbutton and a second normally closed contact included in theenergizing circuit from said energizing source to said lights, saidrelay upon being energized closing said normally open contact to lightsaid light associated with said first pushbutton and opening said firstand second normally closed contact to thereby open the energizingcircuit for said relay associated wtih said second pushbutton and theenergizing circuit for said energizing source to said light associatedwith said first pushbutton.
 5. The electrically interlocking pushbuttoncircuit with error indication of claim 3, wherein said second pushbuttoncomprises a first and a second normally open contact, said firstnormally open contact being included in the energizing circuit for therelay associated with said second pushbutton and being closed when thelatter is operated to energize said relay, said second normally opencontact being included in the energizing circuit for energizing saidlights and being closed when said second pushbutton is operated toprepare said energizing circuit for said lights.
 6. The electricallyinterlocking pushbutton circuit with error indication of claim 5,wherein said relay associated with said second pushbutton comprises anormally open contact included in the energizing circuit for said lightassociated with said second pushbutton, a first normally closed contactincluded in the energizing circuit for the relay associated with saidfirst pushbutton and a second normally closed contact included in theenergizing circuit from said energizing source to said lights, saidrelay upon being energized closing said normally open contact to lightsaid light associated with said second pushbutton and opening said firStand second normally closed contact to thereby open the energizingcircuit for said relay associated with said first pushbutton and theenergizing circuit from said energizing source to said light associatedwith said second pushbutton.
 7. The electrically interlocking pushbuttoncircuit with error indication of claim 6, wherein said energizing sourcecomprises an interrupted source whereby said light associated with saidsecond pushbutton is caused to flash to provide said error indication.8. The electrically interlocking pushbutton circuit with errorindication of claim 7, wherein the energizing circuit from saidenergizing source to the light associated with said first pushbuttonincludes said second normally open contacts of both said first andsecond pushbutton and said second normally closed contact of the relayassociated with said first pushbutton.
 9. The electrically interlockingpushbutton circuit with error indication of claim 8, wherein theenergizing circuit from said energizing source to the light associatedwith said second pushbutton includes said second normally open contactsof both said first and second pushbutton and said second normally closedcontact of the relay associated with said second pushbutton.